The present invention relates to a device for mounting a dividing wall for separating the main air stream and the bypass air in a bypass turbojet engine afterburner.
This wall is arranged inside a cylindrical guide vane casing of the turbojet engine and therewith delineates an annular passage in which the bypass air can flow, which bypass air is intended to be mixed partially with the main air stream flowing inside the wall, downstream of the afterburner.
The dividing wall is fixed at its upstream end to the guide vane casing by means of cylindrical studs which extend radially into the bypass flow and the external end of which is fixed to the guide vane casing and the internal end of which is mounted, with sealing, in a corresponding bore in the wall.
At its downstream end the wall has notches oriented downstream and penetrated by flame holder arms which extend radially from the guide vane casing into the main air stream. Each arm extends some distance from the edge of the corresponding notch in the wall and with this edge defines a cross section through which air from the bypass stream can escape into the main air stream.
The downstream part of this wall is thus mounted with an overhang and can expand freely under the effect of the rise in temperature when the turbojet engine is running.
However, the pressure of the bypass stream is higher than that of the main air stream from the turbojet engine turbine, and this gives rise to significant loadings on the downstream part of the dividing wall and results in local deformations of this downstream part toward the axis of the turbojet engine and in an increase in the aforementioned leakage cross section, thus reducing engine performance.
One known solution to this problem is to stiffen the dividing wall by increasing its thickness and forming stiffeners in its downstream end part. However, this solution is not satisfactory because it is complicated and expensive to achieve and leads to an increase in the mass of the dividing wall—something which is disadvantageous in the aeronautical industry.